One of the early techniques for preparing linear polyalkylene polyamine compounds, such as diethylenetriamine and triethylenetetramine and higher homologs, has been to react an alkyl halide with an amine such as ammonia, ethylenediamine and the like at elevated temperatures and pressures. Generally, high yields of cyclic polyethylene polyamines, e.g., piperazine, aminoethylpiperazine as well as other cyclic amines were produced. Another problem in the process was that hydrohalide salts of ammonia or hydrogen chloride were produced by the reaction, and thus expensive corrosion resistant equipment was required. U.S. Pat. No. 3,751,474 is representative.
More recently, a series of patents disclosed the preparation of linear polyalkylene polyamine compounds by reacting a diol or an alkanolamine compound with an alkylenediamine compound under preselected process conditions. These include:
U.S. Pat. No. 3,714,259 which discloses preparing linear poly(ethylene)amines by contacting ethanolamine with an ethylenediamine compound in the presence of hydrogen and a hydrogenation catalyst. An example of a hydrogenation catalyst is nickel containing copper and chromium components;
U.S. Pat. No. 4,036,881 which discloses the preparation of polyalkylene polyamines by reacting an alkanolamine with an alkyleneamine compound in the presence of a phosphorus-containing substance selected from the group consisting of acidic metal phosphates, phosphoric acid compounds and anhydrides and the phosphate esters; and
U.S. Pat. No. 4,044,053 which is somewhat similar to the '881 Patent except that the alkyleneamine compound is present in an excess amount and a diol is used in place of the alkanolamine.
In French Pat. No. 1,542,359 a process is disclosed for the preparation of poly(ethylene)amines by the polymerization of ethanolamine in the presence of carbon dioxide and a strong base such as potassium carbonate or sodium hydroxide.